Actively speaking two languages protects against cognitive impairment

https://www.uoc.edu/portal/en/news/actualitat/2020/360-bilingualism-alzheimer.html

by elamje • 6 years ago

298 159 6 years ago

uoc.edu

diqwndwqiond3• 6 years ago

Is it correlation or causation tho?

jedberg2• 6 years ago

Looks correlative but it highly correlates, and they did seem to eliminate a lot of confounding factors.

pmichaud• 6 years ago

On priors and given how they sample, I'm guessing it's just p-hacking.

mdtancsa2• 6 years ago

I cant find the episode now, but a few years ago an episode CBC's science show Quirks and Quarks interviewed a researcher that found being bilingual seemed to delay the onset of dementia by a couple of years. Although it doesnt sound like much, from a public policy pov, its pretty significant when you look at what that can mean for quality of life as well as costs for our public health system.

blackbrokkoli3• 6 years ago

You can't get causation from an observation study.

You can however get a lot of attention for "finding" a causation.

So to answer your question, it's quacks selling correlation as causation.

trimbo• 6 years ago

They recruited 63 healthy individuals, 135 patients with mild cognitive impairment such as memory loss, and 68 people with Alzheimer's – the most prevalent type of dementia – in four hospitals in Barcelona and the metropolitan area

Wait so, N = 266? All from Barcelona?

C'mon.

ip262• 6 years ago

With proper random sampling you only need something like N = 27 (I forget exactly) to reach p = 0.05

Assuming random sampling, it's a misconception that you need ten thousand participants to have a useful study.

sillysaurusx• 6 years ago

Cue “p = 0.05 is a random choice” and a big thread about p-hacking. Any takers?

It feels like everything to say has already been said about the bias of small sample sizes and the dangers of p-hacking. But it also seems like the discussion is inevitable here.

I wonder if there’s a new insight to glean, somehow...

For a background on why p-values are misleading, see https://youtu.be/42QuXLucH3Q which is excellent. He points out that 0.05 was selected by Ronald Fischer in 1925, and people have gone with it since.

bluejellybean• 6 years ago

Isn't the crux just that, "proper random sampling" can be quite hard. Assumptions are fine in theory, in reality, they can seriously throw us for a loop.

diqwndwqiond3• 6 years ago

It seems that his objection is he "homogeneity" of the population, they're all from Barcelona, if the sample had different locations I think he wouldn't object the small number( e.g N = 30 ).

refurb• 6 years ago

Your mixing up your statistics. Perfect random sampling of a normal distribution means you can sample 27 times and your statistical analysis is close to that of the entire population.

It's highly dependent on the magnitude of the effect (when comparing two populations) and the distribution across a population.

For something dementia, where even measuring the level of cognitive decline is highly subjective, no way N=27 would be enough.

cik2e• 6 years ago

Also, you only need about 400 samples for 95% confidence on a proportion at the highest variance point of p1 = . 0.50. It used to drive me nuts when my CEO used to say “10 clicks out of 10,000 on this A/B test is in the noise”. No, that’s not in the noise, it’s almost certainly a clickthrough rate of close to 0.

drumttocs8• 6 years ago

Can you explain how N=27 could possibly represent and be extended to billions of humans? It is certainly not intuitive to me.

ekianjo5• 6 years ago

With proper random sampling you only need something like N = 27 (I forget exactly) to reach p = 0.05

will be difficult to demonstrate that they can control for all individual differences at n=266 to prove differences in dementia outcomes are linked to a single variable.

andy_ppp3• 6 years ago

Yes, I haven’t read the paper but how can you control for correlated stuff here, e.g. bilingual people are likely to be richer, more intelligent, exercise more, eat better more varied food and have richer social lives. Maybe.

drdrey• 6 years ago

Are immigrants and their children likely to be richer, eat better, etc?

tropdrop• 6 years ago

This is why they chose Barcelona, where the use of 2 languages (Catalan and Spanish) was "highly variable" and everyone in the city spoke or at least understood 2 languages:

"We wanted to take advantage of this variability, and instead of comparing monolingual and bilingual people, we looked at whether in Barcelona – where everyone is more or less bilingual – there was a certain degree of bilingualism that had neuroprotective benefits."

pier25• 6 years ago

Between Catalan, Basque, and Galician, many people in Spain are bilingual (if not trilingual since English is quite common). Rich, poor, intelligent, idiot, etc.

AmericanChopper3• 6 years ago

Have you got a source for any of that? I imagine a lot of demographic factors could confound such a study, but I don’t see why multilingual people would be richer/healthier/more educated. In a lot of western countries, I’d imagine a huge amount of the multilingual population would be made of less well off immigrants.

not_a_moth• 6 years ago

While sampling equally from different income groups might clear up these variables, from what I've been able to find some of highest rates of dementia are in relatively small rich European countries.

Those countries have longer life expectancies so it's hard to do apples-to-apples for rich countries to poor countries.

I do think the "use it or lose it" model for neurodegeneration makes a lot of sense, in the same way you lose muscles if you don't use them, so bilingual is an interesting proxy for greater brain use. Although I also think the lack-of-sleep model makes sense too so I really don't know.

another1oror• 6 years ago

Another from Italy with 85 people that found the same

https://www.alzheimers.org.uk/news/2018-05-15/bilingual-brai...

This one appears to have brain scans to suggest structural differences do exist

airstrike• 6 years ago

N = 266 isn't really that bad at all

esperent• 6 years ago

What about N = 266, all from one city?

avip• 6 years ago

We did FDA cert. of medical device with way less. With sound methodology this number would be totally ok (depending on strength of measured signal)

roenxi• 6 years ago

Interesting and suggestive, but difficult to interpret from the publicly available information. Actively speaking two languages no doubt implies complex correlations between wealth, status and circumstance.

The paper abstract doesn't mention controlling for location. That would also be an interesting thing to test.

jedberg2• 6 years ago

One of the first things it mentions is controlling for location -- they were all in Barcelona.

bobthepanda• 6 years ago

Which basically makes this a study of Catalan-Spanish bilingualism.

It would be interesting to see if this also applied to other combinations of languages.

7thaccount3• 6 years ago

Or just not being someone born in the USA to non first generation parents.

kingkawn• 6 years ago

The study is in Spain.

Wolfenstein98k• 6 years ago

What does bilingualism correlate with?

k__• 6 years ago

Immigration?

Going to a school in Europe?

Living as a minority with its own language in a country with another language?

S4M• 6 years ago

Or maybe just not being a native English speaker.

hibbelig3• 6 years ago

In the case of the article, it’s about living in a region where more than one language is locally spoken.

smt88• 6 years ago

It depends on the country.

In many countries, wealthier students receive more instruction in a foreign language and have access to full immersion programs.

miltondts• 6 years ago

If I'm not mistaken, speaking two languages in Spain is quite common. The country has multiple languages besides Spanish [1]. So I guess it doesn't correlate with much aside from the geographic region.

[1] https://en.wikipedia.org/wiki/Languages_of_Spain

pvaldes9• 6 years ago

Speaking three is common, but there is often an appreciable and even obvious erosion in the mastery of some of them (limited vocabulary, misspellings..., mobile phones made lot of damage also in this field). We need to be aware of this point also

Having a logically structured thinking or being good in math (all related with having dementia or not) does not depend on how many times you can say 'street' in different languages.

umanwizard5• 6 years ago

FWIW, the study was done in Barcelona, which (along with Montreal) is one of the most fully bilingual cities in the developed Western world.

wombatmobile• 6 years ago

So how does dementia incidence in Montreal compare with mono lingual regions?

ggrrhh_ta2• 6 years ago

I can think of many cities (even in Europe) where many people are fully bilingual (in the Netherlands, Belgium, Switzerland, Sweden, Finland, in some regions of Italy, Austria and Croatia, etc...) - and if we go outside of Europe, well, in India, Ghana, Paraguay, etc... (just to select one instance across other continents), well, I'd say that bilingualism (or multilingualism) is almost a norm...

Etheryte• 6 years ago

Most of the world's population is multilingual [1], hence it doesn't correlate with much anything on a wider scale. The list of multilingual areas is very long and nuanced [2] and the implications and correlations in each location are as widely varied as the list itself.

As other commenters have already pointed out, the study took place in Barcelona, where multilingualism is prominent and doesn't correlate with any specific group or trait.

[1] https://en.wikipedia.org/wiki/Multilingualism#Myths

[2] https://en.wikipedia.org/wiki/List_of_multilingual_countries...

lifeisstillgood2• 6 years ago

I understand the concerns about p-value but the causal pathway is such a clear one (make brain work harder each day and it stays elastic and effective longer) that this should be a slam dunk for more research grants

maroonblazer• 6 years ago

make brain work harder each day and it stays elastic and effective longer

Would this extend to learning in general? E.g. learning more than one musical instrument?

lifeisstillgood2• 6 years ago

I don't know - that's why I think more funding is needed. Directing that funding against likely targets seems a sensible idea.

Until someone finds some bacterial or pathogen cause for Alzheimer's and dementia, funding should go on the "we don't use it we lose it" assumption. Yes there may be other factors of course, and given the surprise over stomach ulcers it's entirely possible the use it or lose it idea is wrong.

But science funding needs to be a smart money play not a scattergun.

medymed• 6 years ago

The causal pathway is exceeding clear with sufficient wishful thinking.

yosito• 6 years ago

the ~~causal pathway~~ hypothesis is such a clear one

aurelianito2• 6 years ago

Almost everyone is bilingual in Barcelona. They teach Catalan and Spanish at school, and both are spoken by the general population. How did they get non-bilingual people there?

lolc2• 6 years ago

"Therefore, unlike in previous studies, the researchers established a bilingualism gradient: from people who speak only one language but are passively exposed to another, to individuals who have excellent proficiency in both and use them indiscriminately on a day-to-day basis. To create this gradient, several variables were taken into account, including the age of acquisition of the second language, the use made of each language, and switching between languages in the same context."

asveikau• 6 years ago

I would expect there to be a fair amount of monolingual Castilian speakers there too. People who moved there from another part of Spain for instance.

aurelianito2• 6 years ago

If they tapped into this population they wouldn't be able to make any valid conclusion because they are intrinsically different.

boulos• 6 years ago

The title has been editorialized unfortunately. The page uses Actively speaking two languages protects against cognitive impairment which is an important summary of the paper: everyone in the study is basically bilingual, but the bilingual composite score (how bilingual you are / how much you actively speak and switch languages) is suggested as a precursor of delayed cognitive decline.

The title of the original paper is Active bilingualism delays the onset of mild cognitive impairment which is also clear, if a little stilted as a headline.

dang• 6 years ago

Ah thanks. We've changed the title now. Submitted title was "Dementia 50% lower in bilingual populations".

Submitters: please follow the site guidelines, which include: "Please use the original title, unless it is misleading or linkbait; don't editorialize."

https://news.ycombinator.com/newsguidelines.html

ummonk• 6 years ago

Seems like something that could easily have causation going the other way (or having a common cause) no? E.g. perhaps people who end up having cognitive impairment stop regularly speaking both languages because it's harder to do so when suffering cognitive decline.

carbocation• 6 years ago

Table 1 shows various demographic factors broken down by disease vs no disease.

But since they're making claims about bilingualism vs no bilingualism, we also need to see a "Table 1" equivalent for those two categories, so we can understand at a glance which confounders are correlated with these values.

Secondarily, it's a bit concerning (for their hypothesis) that bilingualism is associated with less mild cognitive impairment but not with the more severe dementia phenotype.

torben-friis• 6 years ago

This might be me being overly cautious here, but I would be wary of the political implications of the study.

It's from an open University that's a project for lifelong learning funded as a public service in Catalonia - promoting the catalan language in the region is a key point of the project, so studies finding out that bilingualism is something great to have raise red flags about the nationalist agenda behind it.

To be clear, I'm not trying to make a point against catalan people or taking a position in any political side whatsoever. I'm just pointing out the potential for local context affecting the scientific method here.

kiliancs• 6 years ago

It is a common point of view from modern Catalan nationalism that the bilingual status-quo is conducive to the minoritization of the Catalan language long term. Bilingualism can also mean Catalan and English. On the other hand, pro-union parties [0] and organizations [1] often defend bilingualism under the opposite premise: that supposedly Catalan has an advantageous position over Spanish.

[0] https://www.elmundo.es/cataluna/2019/04/25/5cc192b4fdddff712...

[1] http://convivenciacivicacatalana.blogspot.com/p/administraci...

lottin5• 6 years ago

If you see past the rhetoric you will find that Catalan nationalists would like Catalan to be the dominant language in Catalonia while Spanish nationalists would like Spanish to be the dominant language instead. Neither of them are really concerned about English because English is not in a position to replace either Catalan or Spanish.

speedgoose• 6 years ago

I understand your point but you can make the same for a lot of research. You do research on what you get founding for.

They may simply research on topics they get founding and publish the nice results.

lottin5• 6 years ago

In general, Catalan nationalists tend to see bilingualism as a process by which one language (Catalan) is gradually being supplanted by another (Spanish). They are not really advocates for bilingualism.

08234987234987210• 6 years ago

I recall "Catalunya si, España también" being a unionist slogan. Did I misunderstand?

TIL there's an ¡Ay Carmela! movie. Recommended or not?

personlurking• 6 years ago

As an aside, here's a breakdown of who speaks Catalan vs Spanish, in Catalonia, as of 2018:

https://www.idescat.cat/novetats/?id=3446&lang=en

The quick version, in a single image, with the lightest area being the region of Barcelona:

https://i.imgur.com/tPiOuiz.png

esroyo• 6 years ago

Yes It is.

wazoox• 6 years ago

Weird to call it "Spanish". Catalan is also "Spanish" (though you'll find a very small number of speakers in Southern France). Usually Catalan is opposed to Castilian.

marton78• 6 years ago

It would be interesting to see how the described effect depends on linguistic proximity. Does bilingualism of e.g. English and Chinese or German and Turkish protect better against cognitive decline than Castilian and Catalan?

08234987234987210• 6 years ago

That would be interesting. FWIW the US State Department has observed a factor of 3 difference in time to teach anglophones various languages (think dutch vs mandarin) to B2 level:

https://news.ycombinator.com/item?id=24677256

kjaftaedi• 6 years ago

It's always good to be wary, but so far it seems that most studies in this area are in agreement, and that this phenomenon isn't specific to language, it seems to be the same for musicians.

So in theory you could potentially realize similar benefits without learning another spoken language.

fit2rule• 6 years ago

By the same token, anyone claiming that this must be agitprop designed to promote a political agenda, is promoting their own agenda of nationalism.

Vielleicht sind die zweisprachigen Sprecher jedoch besser darauf vorbereitet, die Wahrheit zu finden: Sprache ist Politik - Es wird besser, je mehr Sie es verwenden.

08234987234987210• 6 years ago

Ganz meine Meinung. https://news.ycombinator.com/item?id=23858477

"The facts—man, happening, amount, place, time—are true in each case. They could be sworn to by the whole membership of an interfaith conference. But the interpretation placed on them—who communicates these facts to whom? why? when?—makes them into propaganda."

vmception• 6 years ago

Which could just as easily be a congratulations on the world creating the convoluted incentives to research this

cube00• 6 years ago

Hopefully code is counted as a language so I'll have a 50% lower risk too.

mikeomoto• 6 years ago

This study tries to explain why "some studies have failed to show this bilingual advantage, suggesting that it might depend on the type and degree of bilingualism", by laying out evidence for the "type and degree of bilingualism.

Here are the facts that the article established:

- Lifelong degree of bilingualism predicts delay in age of onset for all clinical measure of Mild Cognitive Impairment (MCI).

- This is NOT true for Alzheimer's Disease patients.

- This prediction was independent of occupation, education, and job attainment.

The second bullet point isn't properly emphasized in the article, but it's directly from the abstract.

The researcher has a hypothesis that multilingualism improves Cognitive Reserve [1], and, and Cognitive Reserve has already been established to have an effect on the timeline of Alzheimer's disease related pathology. [2]

That being said, it's also true that "AD is the most common etiology of MCI and mild dementia" [3], and the researcher has a hypothesis that the multilingualism improves Cognitive Reserve.

Based on the existing hypothesis of how CR and AD interact, the lack of correlation in AD patients could make sense, and should not be seen as counter-evidence to the bilingualism increases CR hypothesis.

[1] https://en.wikipedia.org/wiki/Cognitive_reserve

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3507991/#S2titl...

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4185370/#S5titl...

ekianjo5• 6 years ago

How do you go from studying Catalan and Spanish bilinguism and make a broad generalization To "speaking two langages" ?

We dont know how this translates to other forms of bilinguism at all.

ekianjo5• 6 years ago

This paper suggest causal effect but they have nothing but correlation. There may be other factord at play between people who are bilingual and those who are not. Would be surprising to say the least that one variable explains differences in dementia outcomes...

tumblewit• 6 years ago

In India almost every school teaches you more than one language and due to the diversity in India most kids actively speak two languages. Not only that but as an adult it is also common in workplaces.

jay_kyburz• 6 years ago

Do you think Python and JavaScript Count?

08234987234987210• 6 years ago

Fosho na foriya. Mi peroba lang belta fo da razhdang xiya. :-)

majkinetor• 6 years ago

I am sure that everything counts.

Scientists like to measure natural language against dementia probably because its easier to do then some other form of knowledge (like being good in multiple disciplines).

From the practical standpoint, learning more then 1 one language doesn't make any sense - practical value you get from it is next to 0 compared to for example learning medicine, electronics, IT, math etc.

Especially because it requires the same amount of time.

luckylion• 6 years ago

From the practical standpoint, learning more then 1 one language doesn't make any sense - practical value you get from it is next to 0 compared to for example learning medicine, electronics, IT, math etc.

That may be true if you're living in a country where English is the main language, otherwise adding English has a lot of practical value.

08234987234987210• 6 years ago

Medicine, electronics, IT, and math all take longer than two years...

Compare https://www.state.gov/foreign-language-training/ (600-2200 class hours for B2 proficiency)

anon42422• 6 years ago

[...] practical value you get from it is next to 0 compared to for example learning medicine, electronics, IT, math etc.

Source missing. Seriously though, you sound very certain of your claim so let me at least offer a counterpoint, however anecdotal.

I've had tons of practical value out of some of my language skills. I would not have the career I have today if I hadn't learned English as a second language. Admittedly my third language, German, was a bust, but I blame the way schools teach language for that (grammar, grammar, grammar). My fourth language, Thai, OTOH was a great investment not only because it made it possible for me to be self-sufficient and socialize (and make friends) while living in Thailand, it also was so different from the previous languages I knew that I could feel my mind expanding. Finally, I've also cracked my head at (Mandarin) Chinese but in that case the practical value has been much closer to 0 but it at least made it possible for me to travel around China on my own, which was well worth it at the time for me.

PierceJoy• 6 years ago

Python counts.

ducks

phendrenad22• 6 years ago

How do we know the cognitive impairment isn't causing people to not speak two languages (despite knowing two - as in they can't remember one of them), long before other symptoms appear? The only way to test that is to split a pool of bilingual people into two groups, and forbid one group from using one language. Was that done?

jarvar• 6 years ago

I image it has more to do with the fact that most people aren't exposed to two languages

Agentlien• 6 years ago

I saw a few comments here commenting this. It's a strange perspective to me. The people I know who are bilingual still prefer one language and use the other primarily to speak to people who don't know their primary language.

As an example I am Swedish but fluent in English and Dutch. In my family we use a mix of Swedish and Dutch. But I use Swedish exclusively with anyone else who is Swedish unless someone is in the conversation who only knows English. I have both friends and colleagues who don't speak Swedish (nor Dutch) and I always speak Dutch with my wife's family.

In this context it makes little sense that I'd simply stop using multiple languages, since then I'd be unable to speak to parts of my family, friends, and coworkers.

phendrenad22• 6 years ago

I guess someone might become fluent in a second language for work purposes, and then once retired, may not need to speak that language much.

forgotmypw17• 6 years ago

https://archive.vn/DZJue

dariosalvi782• 6 years ago

What about 4 languages? I use English at work, Italian with my daughter, Spanish with my wife and Swedish on the street.

08234987234987210• 6 years ago

Hej ragazzo, nice golaso!

Four is up there with Charles V[1]: https://news.ycombinator.com/item?id=24513426

[1] who died at 58, due to poor diet and poor (in)breeding? In any case he shan't serve as a good dementia control.

dariosalvi782• 6 years ago

That's actually who.my daughter sometimes speaks! :)

b0rsuk3• 6 years ago

I read and write in English (comments mostly :-) all the time. Now I have a valid excuse to play team shooters regularly.

08234987234987210• 6 years ago

Do team shooters have discussion beyond simple imperatives?

(I've learned a fair amount of spanish from sports, very little of which I could ever use in polite company. A few years ago I met someone's parents, and although I hear about mothers all the time on the pitch, it was memorable as the first time I'd been introduced to a real one.)

tus882• 6 years ago

Who gets the opportunity to do that if you are living in a native tongue land?

augustk• 6 years ago

More or less anyone whose native tongue is not English.

tus882• 6 years ago

Then your not in your native tongue land. That was my point.

08234987234987210• 6 years ago

https://en.wikipedia.org/wiki/List_of_diglossic_regions

I wonder if actively used bureaucratese is far enough from Standard English to count as second lect? "In view of the somewhat nebulous and inexplicit nature of your remit, and the arguably marginal and peripheral nature of your influence within the central deliberations and decisions within the political process, there could be a case for restructuring their action priorities in such a way as to eliminate your liquidation from their immediate agenda."

Bonus clip: https://www.youtube.com/watch?v=g0j2dVuhr6s&t=60

ggrrhh_ta2• 6 years ago

The methodology reminded me of Feynman's story about the "Young's 1937 rats study". The conclusions could have been better supported with simpler yet better methodology (given that, of course, from the nature of subject under study it can only reveal correlations, and could fail to detect unknown confounding factors).

They could have actually gone to hundreds of elderly homes in Barcelona or, for that matter, better, in places where everyone is mostly actively bilingual (central/north Catalonia?) and regions where people are mostly monolinguals (Castille?) and requested anonymized data from medical records with that information (actively spoken languages vs. mental condition), or if that information was not available, to actually request it to be collected across all these centers, and then establish much stronger correlations.

edit: I originally wrote "the methodology was unnecessarily weak for the conclusions", which was wrong to say from my side. We cannot always do what would be best but must do with what is available to us.

mettamage• 6 years ago

Simply my own thoughts, but I think any cognitive activity that is intensely practiced protects against cognitive impairment.

My grandmother reads a lot of novels, including quite complicated ones and does a lot of language puzzles, yet only knows one language. I'm sure that if she would only watch television and not read a lot of (medieval-based) novels and language puzzles, then she will experience cognitive decline earlier in her life.

I think the mantra "use it or lose it" is quite true in nature, in general.

kriro• 6 years ago

Interestingly, my mother started learning a foreign language recently and it got me thinking. Is anyone here well versed in the state of the art of brain plasticity? I always wondered if you could slow down Alzheimer's disease by trying to "outpace" the brain decline by forming new connections at a faster pace. Learning a language was the first thing that came to mind.

I'd also be very interested in a comparison of two language vs. three language. Switzerland would be the obvious choice but children from partners that don't speak the same language and use English as a lingua franca or Canadians with one extra language (Chinese living in Canada etc.) should provide a big enough sample.

tgv• 6 years ago

That study might be not support the wild conclusion in the title.

They determined fluency in two languages (Spanish and Catalan) in people hospitalized in and around Barcelona. There are some hard-core Catalans that hardly --or even refuse to-- speak Spanish there, but not that many in Barcelona, but there are (many) people from other regions in Spain who are not fluent in Catalan, because they started working and living there a long time ago, when speaking Catalan simply was not needed, or perhaps still forbidden. These will be older, poorer and more frequently hospitalized. So they might simply be looking at two very different groups. Not a word about that in the abstract. I can't access the article.

If actively speaking two languages has an influence, I wouldn't expect much of a difference between Spanish and Catalan: they are close enough to be seen as dialects. They should test this on e.g. English/Urdu speakers or Hungarian/Rumanian.

known• 6 years ago

Does it prevent https://en.wikipedia.org/wiki/Asperger_syndrome

blackbrokkoli3• 6 years ago

This is pseudo-science. Please refrain from upvoting.

You cannot prove (or imply) causation via observation. The only method we know to find causation is by setting up an experiment. This study however merely measures variables in a pre-existing context, without injecting independent variables. The only valid result you may extract from this is a correlation, never causation.

Please edit the title to reflect correlation or (IMO preferred) delete the submission, because such bad science surely does not pass the quality barrier of HN.

threatofrain2• 6 years ago

Protection is a term of art and doesn't deduce causality...

This is pseudo-science. Please refrain from upvoting. You cannot prove (or imply) causation via observation. The only method we know to find causation is by setting up an experiment. This study however merely measures variables in a pre-existing context, without injecting independent variables. The only valid result you may extract from this is a correlation, never causation.
Please edit the title to reflect correlation or (IMO preferred) delete the submission, because such bad science surely does not pass the quality barrier of HN.

Hmm...

blackbrokkoli3• 6 years ago

Can you elaborate?

If I say "vegetables save you from cancer" that implies a causation, wouldn't you agree? Just because it does not explicitly say "cause" it still very clearly says "if you do X, Y will happen". Why do you think this is not applicable?

thesz• 6 years ago

I keep saying that brain grows (BDNF, brain-derived neurotrophic factor is released into blood) when body encounter evolutionary familiar stress - hunger, need for endurance and need for force exertion. Basically, brain was made for body to experience less of that stress.

As an example of what BDNF does: endurance exercise is known for elevating serum BDNF levels long-term [1] and endurance exercise has been shown to help with Parkinsons' [2].

Thus, can it be that these speaking two languages experience more of that stresses thorough their life? The article does not suggest that these factors were, well, factored out.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6613032/

[2] https://pubmed.ncbi.nlm.nih.gov/28870627/

https://www.researchgate.net/publication/260394068_Long_term... - they suggest that habitual exercise does not produce more BDNF or it is not BDNF that acts on the brain, I counter that body utilizes it better, just like glucose in blood.

hakeberio• 6 years ago

Learning a new language is often accompanied by the very real feeling of your "mind expanding." I think that's because being able to understand/speak another language is almost like experiencing a whole new world; another rich set of culture, people, literature, etc different from yours suddenly become very much accessible.

The Wittgenstein adage

The limits of my language mean the limits of my world

rings true for me.

Actively speaking two languages protects against cognitive impairment

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